//
// Created by herbert on 18-10-16.
//

#include <iostream>

int main() {
    int sum = 0;
    int v1 = 0, v2 = 0;
    std::cout << "Enter two numbers" << std::endl;
    std::cin >> v1 >> v2;
    int val = v1;
    while (val <= v2) {
        sum += val;
        ++val;
    }
    std::cout << sum << std::endl;
    return 0;
}